Hydraulic suspension system for gyratory crusher shafts



H. BEHR 3,057,563

HYDRAULIC SUSPENSION SYSTEM FOR GYRATORY CRUSHER SHAFTS Oct. 9, 1962Filed Jan. 10, 1961 2 Sheets-Sheet 1 Oc 9, 1 62 H. BEHR 3,057,563

' HYDRAULIC SUSPENSION SYSTEM FOR GYRATORY CRUSHER SHAFTS Filed Jan. 10,1961 2 Sheets-Sheet 2 FIG. 10

INVENTOR Henry Behr ATTO Ri he tats 3,057,563 Patented Oct. 9, 19623,057,563 HYDRAULIC SUSPENSEQN SYSTEM FOR GYRA- TDRY CRUSHER SHAFTSHenry Behr, Wantagh, N.Y., assignor to Kennedy Van Saun Mfg. & Eng.Corp, New York, N.Y., a corporation of Delaware Filed Jan. 10, 1961,Ser. No. 81,802 12 Claims. (Cl. 241-37) My invention relates toimprovements in rock crushers, more particularly, rock crushers of thegyratory type, and in means for hydraulically suspending and controllingthe vertical movements of the shafts of gyratory crushers.

My present invention comprises improvements in gyratory crusherconstructions of the type including hydraulic means for supporting theshafts of the gyratory crushers. As far as known such crushers areprovided with a single relatively large hydraulic cylinder located abovethe crusher shaft and having a piston connected to suspend the shaftfrom a multiplicity of long rods located outside the cylinder andextending down to a point below the top of the shaft.

This structure and the control system provided therefor have involvedcertain problems which have been solved by my present invention. Forexample, the long rods have given trouble because they were always intension and subjected to continuous stretching and loosening. Anotherproblem results from the leakage of hydraulic fluid past the pistonrings of the relatively large piston employed. It was furthermoredifficult to obtain sufliciently close tolerances in the large pistonand cylinder unit to avoid considerable leakage of hydraulic fluid,which became a problem.

Another problem was the difficulty of properly controlling andmaintaining the height of the crusher shaft so that the mantle of thecrusher is maintained in the proper desired relationship with the bowlliner.

Having in mind the problems and difficulties encountered with priorcrusher constructions and operating systems, the primary object of myinvention is to provide an improved hydraulic means for suspending thecrusher shaft of a gyratory crusher so as to minimize the effect of lossof hydraulic fluid and to provide means so that the shaft and the mantlecarried by the crusher shaft is automatically maintained in the desiredcrushing relationship with respect to the bowl liner of the crusher.

Another object of my invention is to provide an automatically responsivehydraulic system which is not only sensitive to the occurrence ofuncrushable objects in the material being crushed but is alsoimmediately sensitive to any loss of hydraulic fluid in the shaftsuspension system.

A further object of my invention is to provide an improved arrangementwhich is extremely sensitive and flexible for changing the crushersetting to compensate for any loss of hydraulic liquid and wear of themantle and bowl liner.

According to my present invention, the improved hydraulic crusher shaftsuspension comprises an annular series of cylinder and piston unitscarried by the hub of the crusher spider and arranged around the upperportion of the crusher shaft, an adjustment header connected to theupper portion of the shaft and having a flange extending peripherallytherefrom over the annular series of cylinder and piston units, meansconnecting said flange to each of the pistons of said cylinder andpiston units and compression members respectively located between saidflange and said pistons for carrying the shaft load.

In this construction the cylinders are filled with hydraulic fluid belowthe pistons and the lower portions of adjacent cylinders areinterconnected for the free flow of hydraulic fluid from one cylinder toadjacent cylinders, so that the hydraulic fluid in all cylinders is atthe same pressure. The hydraulic system for the crusher includes a pumpfor delivering hydraulic fluid to the cylinders at the requiredpressure, and other elements, including a supply tank and anaccumulator. In accordance with an important feature of the presentinvention, an automatic control is provided at the top of the crusherwhich is responsive to a downward movement of the crusher shaft from itsnormal set position, for automatically effecting the supply of hydraulicfluid to the cylinders. Means is provided for adjusting the verticalposition at which the control is actuated in accordance with the desiredsetting for the crushing elements of the crusher. The controlautomatically operates the hydraulic system to supply hydraulic fluid tothe cylinders in the case of any loss therefrom suflicient to materiallychange the normal set height of the crusher shaft. The means forvertically adjusting the position at which the control is actuated isemployed for originally setting the spacing for the crushing elementsand for adjusting them for wear.

My present invention includes other features, objects and advantagesdescribed more in detail hereinafter in connection with a singleembodiment of the invention illustrated in the accompanying drawings.

In the drawings:

FIGS. 1 and 1a are broken vertical sectional views through the upperportion of a gyratory crusher embodying the features of my invention,FIG. la being partly diagrammatic and showing the hydraulic andelectrical systems associated with the crusher proper; and

FIG. 2 is a horizontal sectional view taken on the line 2-2 of FIG. 1,through the upper portion of the crusher showing a part of the structureand arrangement of the hydraulic cylinders.

Referring to the drawings, the features of the invention are describedbelow in connection with a known type of gyratory crusher which includesa spider casting mounted on the crusher frame and a crusher shaftmounted centrally in the crusher carrying a crushing mantle whichcooperates with a crushing bowl liner mounted around the mantle. Thecrusher includes the usual driving means for rotating an eccentricmounted around the lower portion of the shaft and used to gyrate theshaft for the crushing of a stone or rock delivered through the spiderinto the space between the mantle and the bowl liner. Since the featuresof the present invention relate essentially to the upper portion of thecrusher and is concerned with the suspension of the crusher shaft, theother parts of the crusher are not illustrated or described.

The portions of the crusher as shown in FIG. 1 comprise the framecasting 10 onto which the spider casting 12 is bolted. The spidercomprises the usual spaced arms 14 which extend upwardly and inwardlywhere they merge into the spider hub 16. The crusher shaft 18 extendsthrough a spider bushing unit comprising elements 19 and 20 of knownconstruction mounted in the spider hub and adapted to center the upperportion of the shaft in the spider and permit the limited movementsoccasioned by the gyra-tion of the lower end of the shaft. The crushingelements of the gyratory crusher comprise a conical mantle 21 mounted onthe shaft 18 below the bushing unit and a bowl liner 22 mounted oppositethe mantle in the body of the crusher.

The spider hub 16 is cast with a vertical cylindrical section 24extending somewhat above the normal position of the top of the shaft 18,and also with a horizontallyextending flange 26, the periphery of whichmeets the upper surfaces of the arms 14 of the spider. This flange has ahorizontal annular surface 28 which serves as a seat for a unitaryannular casting 30. The formation and arrangement of the cylindricalsection 24' and flange 26 is such as to position the annular casting 30which is provided with a multiplicity of cylinders 32 uniformly spacedaround the spider of the crusher. The cylinders 32 are formed by boringthe annular casting from above, and this casting 30 is secured to theflange 26 by means of stud bolts 34 threaded into the bottom of thecasting at appropriate intervals. The outside of the casting 30, whichextends above the top of the cylinders 32, terminates in a flange 36 towhich an adjustment header cap 38 is bolted.

The cylinders 32 for any particular crusher are all of the same size andare each provided with a piston 40 of considerable depth having suitablesealing rings, as illustrated. Each piston is connected by a bolt 42,threaded into the top of the piston, to an annular outwardlyextendingflange 44 of an adjustment header 46. The bolts 42 respectively extendthrough spacer sleeves 48 of the same length located between therespective pistons and the adjustable header. Castle nuts 50 arethreaded down on the bolts 42 to provide a uniform compression strain onthe sleeves 48.

The lower portion of the adjustment header 46 includes an outercylindrical bearing surface 52 slidable on the bearing surface providedby the inner cylindrical wall of the spider cylinder 24. One or morevertical keys or splines 53 are mounted in grooves in the inner surfaceof the cylinder 24 and are received in matching grooves in the bearingsurface 52 to prevent rotational movement of the adjustment header 46.The lower part of the adjustment header 46 is provided with aninwardly-projecting heavy annular flange 54 for supporting andsuspending the shaft 18. The flange 54 is fitted with and supports aring 56 having an upper convex spherical surface engaged by the lowerconcave spherical surface of a shaft suspension ring 58 fitted on theupper part of the shaft 18 and keyed thereto by a key ring 60 whichextends into an annular groove in the upper part of the shaft 18. Theshaft 18 is suspended on the flange 54 of the adjustment header 46carried by the pistons 40, which in turn are supported by hydraulicfluid in the cylinders 32. The eccentric movements of the upper end ofthe shaft 18 are accommodated by the spherical seats on the members 56and 58.

The lower parts of the cylinder 32 of the entire annular casting 30 areinterconnected by passageways 62 to provide for the distribution ofhydraulic fluid under equal pressure to all of the cylinders. Hydraulicfluid is admitted to the cylinders 32 by a relatively large supply pipe64 connected into the lower part of the casting 30 at the bottom of oneof the cylinders 32, as shown to the right in FIG. 1. This pipe 64extends down along one of the spider arms 14 and is connected into thehydraulic fluid supply system shown diagrammatically in FIG. la. Thecylinders 32 are connected at the top by means of notches or passageways66 connecting adjacent cylinders so that loss of fluid from any of thecylinders 32 will eventually flow around to an overflow pipe 68connected into one of the cylinders slightly below the top, as shown atthe right in FIG. la. The pipe 68 conducts this bydraulic fluid to ahydraulic fluid supply tank 70 as indicated.

The hydraulic fluid supply system as shown at the right in FIG. laincludes the supply tank 70 connected to the intake of a pump 72 drivenby an electric motor 74. The pump 72 is connected to deliver thehydraulic liquid into the pipe 64 and is adapted to provide sufficientpressure in cylinders 32 to raise and maintain the crusher shaft andcrushing mantle head at the desired height under normal operatingconditions. A solenoid operated valve 76 is located in the pipe 64downstream of the outlet of the pump 72. The pump 72 operatescontinuously with hydraulic fluid flowing through the valve 76 andpiping 77 back into the reservoir. When the crusher is to be put inoperation, the solenoid valve 76 is operated directing hydraulic fluidto flow through pipe 64 to the cylinders 4 32 and in turn raise theshaft 18 and crushing head to operating position.

An accumulator tank 78 is connected into the supply line 64 downstreamof the valve 76 by a pipe 80. This tank is provided with a piston 82 andis initially charged with nitrogen through a valved line 84 so thatunder normal operating conditions the tank is completely filled withnitrogen at a pressure of 700 pounds per square inch. The pipe connectedinto the accumulator tank 78 is provided with a pressure-responsivesolenoid valve 86, so that if the pressure applied by the pistons 40 inthe cylinders 32 exceeds a predetermined limit point, due to thepresence of tramp iron or other uncrushable objects in the crushingcavity, valve 86 will be opened and hydraulic fluid will be displacedinto the accumulator 78, thereby allowing the shaft and crushing head todrop sufliciently to permit the tramp iron to discharge from the cavity.As soon as this happens the pressure of the hydraulic fluid in thesystem will return to normal, since the excess hydraulic fluid forcedinto the accumulator 78 will be driven back into the cylinders 32,thereby raising the shaft and crushing head to its normal crushingposition.

One of the important features of the present invention included in thehydraulic suspension system, as shown in FIG. 1, is the provision of acontrol switch 88 located within the adjustment header 46 and operableby an adjustable actuating means 90 mounted on a control ring 92 locatedslightly above the shaft 18 and supported by three brackets 94 extendingupwardly and attached to the top of the adjustment header 46. Thecontrol switch 88, which is biased to closed position but normally heldopen by the actuating means 90, is mounted on a verticallyadjustablegauge bar 96 extending through an opening in control ring 92 and alsothrough a switch cover plate 98 fitted in the top of the adjustmentheader cap 38. The control switch 88 and mounting bar 96 are verticallyadjustable by means of a threaded rod 100 secured to the switchmounting, extending through the cover plate 98 and provided with a nut101 secured thereto. The rod 100 is rotatable in the switch mounting andis threaded up or down in the nut 101 by means of a handle 102. A remotecontrol may be provided to make the adjustment. The upper ends of theswitch mounting means 96 and rod 100 are covered by an enclosure 103provided with a removable cap 104.

The switch 88 is electrically connected through current leads 106 and108 through a current supply source 110 with the solenoid valve 76. Thecurrent leads 106 and 108 extend through an electrical cable casing 112into a junction box 114 and through a cable line 116 to the switch 88.Electric current is supplied from the current supply leads 110 to themotor 74 by connections 120, one of which is provided with an off-onswitch 122.

The hydraulic system, as shown in FIG. 1a, advantageously includes acheck valve 124 in the pipe 64 between the solenoid valve 76 and pipe80, a relief line 126 provided with a pressure reducing valve 128connected to discharge hydraulic fluid from the pipe 64 to thereservoir, a relief line 130, provided with a hand valve 132 and havingconnections for direct flow from the pipe 64 downstream of check valve124 to the reservoir 7 0, and a relief line 134, provided with a handvalve 136, connected for discharge of hydraulic fluid from theaccumulator 78 and the line 80* above the valve 86 into the reservoir70. The solenoid valve 86 is connected by one lead 138 with the currentlead 106 which in turn is connected with one of the current supply leads110 through a start and stop switch 140. A second lead 142 connects thevalve 86 with a pressure switch 144 responsive to the pressure in thepipe 64. A current lead 146 completes the circuit to the other currentsupply lead 110.

During the operation of the crusher, the height of the adjustment header46 and of the shaft 18 may be adjusted upwardly by raising the controlswitch 88 relative to the adjustment header 46 and the means 90. As theswitch 88 is raised slightly it closes and causes actuation of thesolenoid valve 76 to cut off the flow through the pipe 77 and direct theflow through the pipe 64 and check valve 124 so that additionalhydraulic fluid is pumped into the cylinders '32. As the shaft 18 andadjustment header 46 are raised by the additional hydraulic fluid, theactuating means 98 is also raised and at the selected height opens theswitch 88, thereby changing the solenoid valve 76 to put the pump onclosed cycle.

In an emergency the shaft 18 and the adjustment header 46 may be loweredby opening the hand valve 132, so that hydraulic fluid flows from thecylinders 32 through pipes 64, 80, 138 and 77 into the reservoir 70.Such an emergency may occur if the crusher has been stalled byoverloading and is loaded with stone. The lowering of the crusher shaft18 and crushing head permits the clearing of the crusher cavity withoutdigging out the stone by hand. When the adjustment header 46 is loweredby opening the valve 132, the switch 88 is permitted to close andactuate valve 76, but the hydraulic fluid delivered by the pump 72through the valve 76 into the pipe 64 will merely flow through the pipes88, 130 and 77 back into the reservoir 70. If the crusher is to be outof operation for long, the switches 122 and 140 are opened.

If there should be any loss of hydraulic fluid from around any of thepistons 40, it drains back into the reservoir 70 and may eventuallycause the control ring 92 to drop away from the control switch 88sufficiently to permit it to close. When this switch is actuated toclosed position, the solenoid valve 76 is actuated and the hydraulicfluid lost from the cylinders is replaced and the control ring 92 andactuator 90' elevated until the control switch 88 is opened.

The pressure setting initially made by turning the adjusting screw 1%may be changed to compensate for wear of the crushing members by turningthe screw 100 upwardly to raise the switch 88. The bar 96 on which theswitch is mounted may be graduated as shown for the purpose of measuringthe amount of any adjustment to be made in the height of the shaft 18.

Under normal operating conditions, with the crusher shaft 18 supportedand suspended by the hydraulic fluid in the cylinders 32, the shaft 18is automatically maintained at approximately the predetermined crushingheight setting, but is automatically permitted to move downwardly byoperation of the safety system when an uncrushable object, such as apiece of tramp iron, comes between the crushing elements and applies ahigh pressure to the hydraulic fluid in the cylinders. The downwardmovement of the shaft 18 under such conditions is effected suddenly whenthe pressure on the hydraulic fluid in the cylinders 32 and pipe 64reaches about 1000 pounds per sq. in., the operating pressure for whichthe switch 144 is set to open the solenoid valve 86. When this valveopens at this high pressure, hydraulic fluid from the cylinders rushesinto the accumulator 78 and permits the downward movement of the shaft18. As soon as the uncrushable object has passed through the crushingelements, the pressure applied by the shaft 18 is reduced and the highlycompressed nitrogen in the accumulator 78 forces hydraulic fluid backinto the cylinders 32, so that the shaft 18 is raised quickly to itsnormal height.

The switch 144 is set to open at 400 pounds per sq. in., a pressuresomewhat above that normally required in the cylinders 32 to keep thecrusher shaft in crushing position. The solenoid valve 86 is biased toclosed position and it therefore closes when the switch 144 opens. Whenthe shaft 18 is permitted to move down suddenly under the conditionsdescribed above, upon the closing of the switch 144, the switch 88 abovethe shaft 18 closes, but means is provided so that the actuation of thesolenoid valve 76 is prevented and excess hydraulic fluid is not pumpedinto the pressure side of the system. Closing of the pressure switch 144sends electric current from the current lead 142 through a current lead148, including a relay 150, which opens a normally closed switch 152 inthe current lead 108 connected into the solenoid valve 76. After theuncrushable object has passed through the crushing elements of thecrusher and the pressure switch 144 opens, the relay is de-energized andthe switch 152 closes, restoring the circuit for the normal operation ofthe solenoid valve 76 by the switch 88. The solenoid valve 76 isnormally biased to direct the flow from the pump in closed cycle throughthe pipe 77 and back to the reservoir 70.

The pipe 126 containing the pressure relief valve 128 is provided foremergency purposes for relief of hydraulic fluid from the cylinders 32,the valve 128 being set to open at a pressure of 1100' lbs. per squareinch. However, under most conditions, since the switch 144 opens thesolenoid valve 86 at 1000 lbs. per square inch, the piping leading tothe accumulator cylinder 78 should be able to accommodate the flow ofhydraulic fluid from the cylinders 32. Sudden extreme pressures,however, may cause the relief valve 128 to open momentarily. The pipe134 containing the valve 136 is provided for the purpose of relievingexcess hydraulic fluid from in front of the piston 82 when the solenoidvalve 86 is closed. Under normal operating conditions, the piston 82 isat the extreme left end of the cylinder 78 and held there by thecompressed nitrogen in the cylinder. The accumulator cylinder 78 is,therefore, always in the ready condition and has a capacity forreceiving all of the hydraulic fluid dumped suddenly from the cylinders32. The safety arrangement provided in the system, including theaccumulator cylinder 78, the solenoid valve 86 and thepressure-responsive switch 144, is always available to protect thecrusher from damage which might result from an uncrushable object comingbetween the crushing elements, and to restore the crusher shaft to itsnormal operating position the instant the uncrushable object passes frombetween the crushing elements of the crusher.

While the control system, as shown in FIGS. 1 and la has been describedin connection with the use of certain electrical circuits for effectingoperation of valves and other elements, it is to be understood that apneumatic or hydraulic system may be used to effect the variousoperations and be responsive to the movements of the crusher shaft. Itis also to be understood that instead of providing the cylinders 32 in asingle annular casting, individual cylinder units may be used andapproprlate interconnections provided.

The crusher construction and automatic system provided by the presentinvention has the advantage that in the use of the multiple piston andcylinder arrangement surrounding the upper portion of the crusher shaft,the bolts 42 are used for positioning only and take no load under anyconditions. The entire load is carried by the sleeves 48 surrounding thebolts and they are in compression at all times. Furthermore, themultiple piston and cylinder arrangement makes it possible to provideclose tolerances between pistons and cylinders,

not possible with a single large cylinder, and to thereby reduceleakage. The use of the circular series of pistons and cylindersarranged around the outside of the shaft materially decreases theheadroom above the crusher.

I claim:

1. In a gyratory crusher including a main frame, a spider frame mountedon the main frame and having a centrally located hub at its upper endprovided with a bushing, a shaft located in the crusher and mounted forgyratory motion with its upper portion extending through and projectingabove said bushing, and a hydraulic suspension at the upper part of thecrusher connected with and suspending the shaft, the improvement inwhich the hydraulic suspension for the shaft comprises a circular seriesof hydraulic cylinder and piston units mounted on the spider frame, aheader means connected to the upper end of the shaft for suspending theshaft in the crusher, said header including a peripheral portionextending outwardly over the piston and cylinder units, means forconnecting each of the pistons of said units to said projecting portionof the header means, and means for supplying hydraulic fluid underpressure to the cylinders of said units below the pistons therein.

2. A gyratory crusher as claimed in claim 1, including a compressionspacer between each piston and the projecting portion of the headermeans.

3. A gyratory crusher as claimed in claim 2, in which the compressionspacer is a sleeve surrounding the means for connecting the piston tothe projecting portion of the header means.

4. A gyratory crusher as claimed in claim 1, in which the hub of thespider frame includes a cylinder surrounding the upper part of the shaftand being open at the top, and a horizontal flange extending outwardlyfrom said cylinder and supporting the circular series of cylinder andpiston units outside and surrounding the cylinder.

5. A gyratory crusher as claimed in claim 4, in which the header meanscomprises a cylinder having an outer bearing surface slidable on theinner surface of the spider frame cylinder, the projecting portion ofthe header means comprising an annular flange extending from the upperend of the header cylinder over the circular series of hydrauliccylinder and piston units.

6. In a gyratory crusher including a main frame, a spider frame mountedon the main frame and having a centrally located hub at its upper endprovided with a bushing, a shaft located in the crusher and mounted forgyratory motion with its upper portion extending through and projectingabove said bushing, and a hydraulic suspension at the upper part of thecrusher connected with and suspending the shaft, the improvement inwhich the hydraulic suspension for the shaft comprises a circular seriesof hydraulic cylinder and piston units mounted on the spider frame, aheader means connected to the upper end of the shaft for suspending theshaft in the crusher, said header including a peripheral portionextending out wardly over the piston and cylinder units, means forconnecting each of the pistons of said units to said projecting portion,means for supplying hydraulic fluid under pressure to the cylinders ofsaid units below the pistons therein, and control means responsive tothe upward movement of the shaft and header for stopping the flow ofhydraulic fluid to the cylinders when the shaft is raised to apredetermined height.

7. A gyratory crusher as claimed in claim 6, in which the means forsupplying hydraulic fluid includes a pipe, a valve in the pipe forstopping the flow of hydraulic fluid, said control means including meansacted on by the header and means in turn acting on said valve.

8. In a gyratory crusher including a main frame, a spider frame mountedon the main frame and having a centrally located hub at its upper endprovided with an axial bushing, a crusher shaft located in the crusherand mounted for gyratory motion with its upper portion extending throughand projecting above said bushing, and a hydraulic suspension at theupper part of the crusher connected with and suspending the shaft fromthe spider frame, the improvement in which the hydraulic suspensioncomprises a circular series of hydraulic cylinder and piston unitsmounted on the spider frame surrounding the upper portion of the shaft,a header means connected to the upper end of the shaft and including aperipheral portion extending outwardly over the pistons and cylinderunits, means for connecting each of the pistons of said units to saidprojecting portion, means including a pipe for supplying hydraulic fluidunder pressure to the cylinders of said units below the pistons therein,an electrically operable valve in said pipe, an electric switchconnected to said electrically operable valve for effecting itsoperation, and means movable upwardly and downwardly by thecorresponding movements of the shaft for actuating said switch, theswitch being connected in such a manner with said electrically operablevalve that the valve is closed to cut off the flow of hydraulic fluid tothe cylinders when the shaft attains a predetermined height.

9. A gyratory crusher as claimed in claim 8, including a fixed headercap extending over the header, vertically adjustable means connectedwith the header cap supporting the electric switch at a position abovethe top of the shaft, said means movable upwardly and downwardly beingattached to the header means.

10. In a gyratory crusher of the type including a main frame, a spiderframe mounted on the main frame and having a centrally located hub atits upper end provided with a bushing, a crusher shaft carrying acrushing element located in the crusher and mounted for gyratory motionwith its upper portion extending through and projecting above saidbushing, a hydraulic suspension at the upper part of the crusherconnected with and suspending the shaft in crushing position,, a headermeans connected to the upper end of the shaft for suspending the shaftin the crusher, said header including a peripheral portion connected tothe hydraulic suspension, a reservoir for hydraulic fluid, a pumpconnected into the reservoir for supplying hydraulic fluid underpressure to the hydraulic suspension, a pipe connecting the outlet ofthe pump with the hydraulic suspension, and a control valve in saidpipe, the improvement comprising a pipe connected into said controlvalve for conducting hydraulic fluid delivered thereto from the pumpinto the reservoir, and control means responsive to the downward andupward movement of the shaft and header for actuating said control valveto respectively direct the flow of hydraulic fluid from the pump to thesuspension system and to the reservoir.

11. A gyratory crusher as claimed in claim 10, including a pipecontaining a normally closed control valve connected into the pipeconnecting the outlet of the pump with the hydraulic suspension at apoint between the suspension and the control valve therein, meansresponsive to a rise in the pressure of the hydraulic fluid in thesuspension above a predetermined pressure for opening said normallyclosed control valve and thereby permitting the hydraulic fluid in thesuspension to flow therethrough and permit the crusher shaft to movedownwardly, and means responsive to the actuation of the pressure riseresponsive means for preventing the actuation of the control valve inthe pipe leading to the suspension in a way to send hydraulic fluid fromthe pump to the suspension.

12. In a gyratory crusher of the type including a main frame, a spiderframe mounted on the main frame and having a centrally located hub atits upper end provided with a bushing, a crusher shaft carrying acrushing element located in the crusher and mounted for gyratory motionwith its upper portion extending through and projecting above saidbushing, a hydraulic suspension at the upper part of the crusherconnected with and suspending the shaft in crushing position, a headermeans connected to the upper end of the shaft for suspending the shaftin the crusher, said header including a peripheral portion connected tothe hydraulic suspension, a reservoir for hydraulic fluid, a pumpconnected into the reservoir for supplying hydraulic fluid underpressure to the hydraulic suspension, a pipe connecting the outlet ofthe pump with the hydraulic suspension, a control valve in said pipe, anaccumulator pressurized with gas, a pipe containing a normally closedcontrol valve connecting the accumulator into said pipe between thesuspension and the control valve in said pipe, and means responsive to arise in the pressure of the hydraulic fluid in the suspension above apredetermined pressure for opening the normally closed control valve andthereby permit hydraulic fluid in the suspension to flow into theaccumulator and permit the crusher shaft to move downwardly, theimprovement comprising a pipe connected into the control valve in thepipe connected into the pump outlet for conducting hydraulic fluiddelivered thereto from the pump into the reservoir, control meansresponsive to the downward and upward movement of the shaft and headerfor actuating said control valve to respectively direct the flo-w ofhydraulic fluid from the pump to the suspension system and 5 to thereservoir, and means responsive to the actuation of thepressure-rise-responsive means for preventing the actuation of thecontrol valve in the pipe leading to the suspension in a way to sendhydraulic fluid from the pump to the suspension.

References Cited in the file of this patent UNITED STATES PATENTSNewhouse May 1, 1934 Traylor May 11, 1937 Mcllvried ..t. Dec. 12, 1939Behr July 16, 1957 Hardinge n Oct. 20, 1959

